This relates generally to electronic devices with displays and, more particularly, to electronic devices with displays having adaptive color gamuts.
Electronic devices such as computers, media players, cellular telephones, set-top boxes, and other electronic equipment are often provided with displays for displaying visual information.
Displays such as organic light-emitting diode (OLED) displays typically include an array of display pixels. Each display pixel may include one or more colored subpixels (e.g., a red subpixel, a green subpixel, and a blue subpixel) for displaying color images.
In some types of OLED displays, each colored subpixel is formed from colored OLED material (i.e., OLED material that emits light of a given color). With this type of configuration, each display pixel typically includes a red OLED subpixel formed from red OLED material (sometimes referred to as a red “emitter”), a green OLED subpixel formed from green OLED material (sometimes referred to as a green “emitter”), and a blue OLED subpixel formed from blue OLED material (sometimes referred to as a blue “emitter”). Each color of light-emitting material is deposited on a display substrate in a separate color patterning step.
In other types of OLED displays, colored subpixels are formed by covering white OLED material (sometimes referred to as a white “emitter”) with color filter material. For example, an OLED display can be formed by covering an array of white OLED emitters with an array of red, green, and blue color filter elements (sometimes referred to as an RGB color filter array). The fabrication process used to manufacture an OLED display based on white emitters with an RGB color filter array can be less costly and less complex than that used to manufacture an OLED display based on patterned RGB emitters. However, because light is required to pass through a color filter, OLED displays based on white emitters with color filters are typically less power efficient than those based on patterned RGB emitters.
To increase the power efficiency of OLED displays based on white emitters, some displays employ an RGBW pixel array in which each subpixel includes a red subpixel formed from a white emitter covered with a red color filter, a green subpixel formed from a white emitter covered with a green color filter, a blue subpixel formed from a white emitter covered with a blue color filter, and a white subpixel formed from a white emitter without a color filter. Because the white subpixel does not include a color filter, it typically consumes significantly less power than red, green, and blue subpixels. Rendering colors using the white subpixel in combination with red, green, and blue subpixels may therefore increase the power efficiency of a display.
It can be challenging, however, to achieve sufficient power efficiency using the white subpixel without negatively affecting the color gamut of the display. For example, increasing the luminance contribution from the white subpixel to display a given color will result in lower power consumption but may also make it difficult to accurately display highly saturated colors. On the other hand, a luminance contribution from the white subpixel that is too low can require an excessive amount of power.
It would therefore be desirable to be able to provide improved ways of displaying images on displays such as OLED displays.